package LanQiao.jichu;

import java.util.Scanner;

//FJ的字符串
public class BASIC_22 {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        int N = input.nextInt();
        FJstring(N);
    }

    private static void FJstring(int n) {
        if (n == 1) {
            System.out.print('A');
        } else {
            FJstring(n-1);
            System.out.print((char)('A' + n-1));
            FJstring(n-1);
        }
    }
}
